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<title>pcre2_compile specification</title>
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<h1>pcre2_compile man page</h1>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>
<p>
This page is part of the PCRE2 HTML documentation. It was generated
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please consult the man page, in case the conversion went wrong.
<br>
<h2>
SYNOPSIS
</h2>
<p>
<b>#include &#60;pcre2.h&#62;</b>
</p>
<p>
<b>pcre2_code *pcre2_compile(PCRE2_SPTR <i>pattern</i>, PCRE2_SIZE <i>length</i>,</b>
<b>  uint32_t <i>options</i>, int *<i>errorcode</i>, PCRE2_SIZE *<i>erroroffset,</i></b>
<b>  pcre2_compile_context *<i>ccontext</i>);</b>
</p>
<h2>
DESCRIPTION
</h2>
<p>
This function compiles a regular expression pattern into an internal form. Its
arguments are:
<pre>
  <i>pattern</i>       A string containing expression to be compiled
  <i>length</i>        The length of the string or PCRE2_ZERO_TERMINATED
  <i>options</i>       Primary option bits
  <i>errorcode</i>     Where to put an error code
  <i>erroffset</i>     Where to put an error offset
  <i>ccontext</i>      Pointer to a compile context or NULL
</pre>
The length of the pattern and any error offset that is returned are in code
units, not characters. A NULL pattern with zero length is treated as an empty
string. A compile context is needed only if you want to provide custom memory
allocation functions, or to provide an external function for system stack size
checking (see <b>pcre2_set_compile_recursion_guard()</b>), or to change one or
more of these parameters:
<pre>
  What \R matches (Unicode newlines, or CR, LF, CRLF only);
  PCRE2's character tables;
  The newline character sequence;
  The compile time nested parentheses limit;
  The maximum pattern length (in code units) that is allowed;
  The additional options bits.
</pre>
The primary option bits are:
<pre>
  PCRE2_ANCHORED           Force pattern anchoring
  PCRE2_ALLOW_EMPTY_CLASS  Allow empty classes
  PCRE2_ALT_BSUX           Alternative handling of \u, \U, and \x
  PCRE2_ALT_CIRCUMFLEX     Alternative handling of ^ in multiline mode
  PCRE2_ALT_EXTENDED_CLASS Alternative extended character class syntax
  PCRE2_ALT_VERBNAMES      Process backslashes in verb names
  PCRE2_AUTO_CALLOUT       Compile automatic callouts
  PCRE2_CASELESS           Do caseless matching
  PCRE2_DOLLAR_ENDONLY     $ not to match newline at end
  PCRE2_DOTALL             . matches anything including NL
  PCRE2_DUPNAMES           Allow duplicate names for subpatterns
  PCRE2_ENDANCHORED        Pattern can match only at end of subject
  PCRE2_EXTENDED           Ignore white space and # comments
  PCRE2_FIRSTLINE          Force matching to be before newline
  PCRE2_LITERAL            Pattern characters are all literal
  PCRE2_MATCH_INVALID_UTF  Enable support for matching invalid UTF
  PCRE2_MATCH_UNSET_BACKREF  Match unset backreferences
  PCRE2_MULTILINE          ^ and $ match newlines within data
  PCRE2_NEVER_BACKSLASH_C  Lock out the use of \C in patterns
  PCRE2_NEVER_UCP          Lock out PCRE2_UCP, e.g. via (*UCP)
  PCRE2_NEVER_UTF          Lock out PCRE2_UTF, e.g. via (*UTF)
  PCRE2_NO_AUTO_CAPTURE    Disable numbered capturing paren-
                            theses (named ones available)
  PCRE2_NO_AUTO_POSSESS    Disable auto-possessification
  PCRE2_NO_DOTSTAR_ANCHOR  Disable automatic anchoring for .*
  PCRE2_NO_START_OPTIMIZE  Disable match-time start optimizations
  PCRE2_NO_UTF_CHECK       Do not check the pattern for UTF validity
                             (only relevant if PCRE2_UTF is set)
  PCRE2_UCP                Use Unicode properties for \d, \w, etc.
  PCRE2_UNGREEDY           Invert greediness of quantifiers
  PCRE2_USE_OFFSET_LIMIT   Enable offset limit for unanchored matching
  PCRE2_UTF                Treat pattern and subjects as UTF strings
</pre>
PCRE2 must be built with Unicode support (the default) in order to use
PCRE2_UTF, PCRE2_UCP and related options.
</p>
<p>
Additional options may be set in the compile context via the
<a href="pcre2_set_compile_extra_options.html"><b>pcre2_set_compile_extra_options</b></a>
function.
</p>
<p>
If either of <i>errorcode</i> or <i>erroroffset</i> is NULL, the function returns
NULL immediately. Otherwise, the yield of this function is a pointer to a
private data structure that contains the compiled pattern, or NULL if an error
was detected. In the error case, a text error message can be obtained by
passing the value returned via the <i>errorcode</i> argument to the
<b>pcre2_get_error_message()</b> function. The offset (in code units) where the
error was encountered is returned via the <i>erroroffset</i> argument.
</p>
<p>
If there is no error, the value passed via <i>errorcode</i> returns the message
"no error" if passed to <b>pcre2_get_error_message()</b>, and the value passed
via <i>erroroffset</i> is zero.
</p>
<p>
There is a complete description of the PCRE2 native API, with more detail on
each option, in the
<a href="pcre2api.html"><b>pcre2api</b></a>
page, and a description of the POSIX API in the
<a href="pcre2posix.html"><b>pcre2posix</b></a>
page.
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>
